Compact, low profile, single feed, multi-band, printed antenna

Abstract

Printed circuit techniques and two-shot molding techniques are used to form a metal radiating element, a metal ground plane element, a metal antenna feed, a metal short-circuiting strip and metal capacitive loading plates within small antennas that are buried within transmit / receive radio-devices such a mobile cellular telephones. Balanced and unbalanced, single-feed, two and three band antennas are provided wherein the radiating element is laterally spaced from the ground plane element, to thereby provide an antenna having a very low profile or height, including antennas wherein the ground plane element and the radiating element are placed coplanar on the same surface of a PCB. A thin dielectric carriage on a PCB allows for the metal capacitive loading plates to be placed on the sidewalls of the dielectric carriage, to thereby provide reactive loading of a radiating element that is on the top surface of the dielectric carriage.

Description

FIELD OF THE INVENTIONThis invention relates to the field of radio communication, and more specifically to antennas for use with, or buried within, relatively small radio communication devices, of which mobile cellular telephones are a non-limiting example.BACKGROUND OF THE INVENTIONIn wireless voice and data communications systems, including mobile systems having multi-band and multi-system capabilities, reducing the physical size of the radio transmit / receive devices, such as mobile cellular telephones, is an important design consideration.For radiating / receiving antennas that are buried within the radio-devices (i.e. internal-antennas), the need to reduce the physical size of the radio-devices imposes a severe constraint on the physical volume within each radio-device that is allowed for an internal-antenna and its radiating / receiving element (hereafter called radiating element).A planar inverted-F antenna (PIFA) is commonly used as a radio-device's internal-antenna. A reduction ...

AI Technical Summary

Benefits of technology

"This patent describes various embodiments of printed-antennas that are compact and have a low profile, making them suitable for use in commercial applications such as cellular phones. These printed-antennas have a single-feed, multi-band design that can operate in either a balanced or unbalanced condition. They offer high levels of cross polar radiation and can be easily integrated onto printed circuit boards or chassis of radio-devices. The printed-antennas have a radiating element that can be formed on a PCB or a dielectric carriage, and they can be positioned parallel or perpendicular to the ground plane of the PCB. The invention also provides a multi-band printed-antenna that does not require an external impedance matching network and can be used in either a balanced or unbalanced condition."

Problems solved by technology

A reduction in the physical volume that is available within the radio-device for housing the PIFA's radiating element results in a negative impact on both the bandwidth and the gain of the PIFA.

In addition, with a trend toward restricting the height of such internal-antennas to from about 3 millimeters (mm) to about 5 mm, it is difficult to provide a multi-band PIFA that has a requisite bandwidth and gain.

Although it may be that a PIFA design that is associated with a photonic band gap (PBG) structure can be used to overcome the negative effects of such a reduced height, the associated geometric configuration that is imposed by the design of a ground plane for such a PIFA that includes the PBG phenomenon is difficult.

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